How to Set Up Google Voice as a Voicemail for My Cell Number? [Solved]
It seems that with most of the carriers changing phones or making much of a change to the service will drop the forwarding.
You say "The only option is to have calls to my cell number to forward to Google Voice, which is sort of the opposite of what I want." ... But isn't that exactly what you want? You ultimately have to get your calls to GV in order for it to be your voicemail.
An alternative method is to just dial the T-Mobile forwarding code to activate conditional call forwarding. Just dial *004*[your google voice phone number]*11# (if you have a separate GV number) then press Call as if you were making a regular phone call.
You can use this same code to forward to any other phone number or voicemail service. If more reliable voicemail transcription is desired, that is the same method you would use to set up service with www.TalkScribe.com
A simple method to set up Google Voice as a voicemail for my cell number?
Go to https://www.google.com/voice#phones on a computer and select "Activate Google voicemail on this phone" next to your mobile number
Then follow the instructions provided on the page.
If you do not see that option, you may have to first click "Deactivate Google voicemail on this phone" and then click OK on the subsequent page. If you don't see that option either, click Edit next to the phone number and make sure it is set up as a Mobile phone.
This typically happens if you get a new sim card which loses your call forwarding settings.